Circuit breaker with improved auxiliary switch actuator

ABSTRACT

A circuit breaker including an actuator for operating an auxiliary switch prior to the closing of the main contacts of the circuit breaker. The circuit breaker operating mechanism is of a known type having a movable contact mounted on a movable arm, the movable arm being coupled to a manual operating handle via a collapsible linkage and pivotally supported from a main frame. The actuator comprises a member coupled to the movable arm adjacent one end thereof by a slotted connection, engageable with an auxiliary switch at its other end depending on the position of the movable arm, and pivotally supported from the circuit breaker main frame intermediate its ends.

United States Patent Nicol 1 1March 13, 1973 1 1 (CIRCUIT BREAKER WITH IMPROVED 3,284,731 11/1966 Nicol ..335 |3 AUXILIARY SwlTCH ACTUATOR 2,760,028 8/1956 Walker ..335 |3 [75] Inventor: Ronald Nicol, Trenton, NJ. Primary Examiner Ham|d Broome [73] Assignee: Heinemann Electric Company, mmmeyrrjoseph yi et Trenton, NJ.

[57] ABSTRACT 22 Filed: Dec.6, 1971 A circuit breaker including an actuator for operating pp 204,850 an auxiliary switch prior to the closing of the main contacts of the circuit breaker. The circuit breaker 521 u.s.c| ..33s/13,335/17 Warming mechanism is a tYPe having 3 [5H m CI 01h 73/12 movable contact mounted on a movable arm, the i movable arm being Coupled to a manual Operating [58] Field of Search ..335/l3,17 handle via a collapsiblc linkage and pivotally p ported from a main frame. The actuator comprises a [56] References cued member coupled to the movable arm adjacent one end UNITED STATES PATENTS thereof by a slotted connection, engageable with an auxiliary switch at its other end depending on the posi- 3,217,125 11/1965 Brackett ..335/13 i n f the movable arm, and pivotally supported from 3,307,122 2/1967 g -335/13 the circuit breaker main frame intermediate its ends. 3,530,412 9/1970 Gryetho .......335/l3 3,388,357 6/1968 Lawson et a1. ..335/13 13 Claims, 4 Drawing Figures 26 (Z (0 2 ,1; Q 70 l O l 57 4 .5; f 11:5 O 68 I .57

69 (D Q 40 33' (I CIRCUIT BREAKER WITH IMPROVED AUXILIARY SWITCH ACTUATOR BACKGROUND OF THE INVENTION for addition to a known circuit breaker to operate an auxiliary switch means more accurately and reliably.

Auxiliary switches have been used in conjunction with circuit breakers for many years to indicate the condition of the circuit breaker at a remote location. In accordance with the prior art, the auxiliary switch means has been located so that its actuator, which is commonly a spring biased plunger, is depressed by the movable contact arm on the movement of the arm toward the contacts closed position of the circuit breaker. The actuator of the auxiliary switch means of this arrangement is released by the movement of the movable arm toward the contacts open position of the circuit breaker, so that whether the circuit breaker contacts are opened manually or whether the contacts are opened automatically upon the occurrence of a preselected electrical condition, the auxiliary switch means will be actuated to indicate at a remote location that the circuit breaker contacts are open.

In the type of prior art arrangement noted above the actuator of the "auxiliary switch means is at rest or under a minimum of bias when the circuit breaker contacts are open, and is placed under a greater bias when the circuit breaker contacts are closed. Since the contacts closed position is the normal position for the circuit breaker, such an arrangement results in an unnecessary strain being placed upon the actuator of the auxiliary switch.

Furthermore, according to the above noted prior art arrangement, if it is required to actuate the auxiliary switch means prior to the closing of the main contacts, provision is made for the movable contact arm to engage and depress the plunger of the auxiliary switch at a point earlier in its movement toward the contacts closed position. Since the movable contact arm must continue beyond this point of contact to a large extent, some means must be provided to absorb this additional motion without damage to the auxiliary switch means.

The prior art has commonly utilized a resilient member for this purpose to takeup or absorb the additional motion of the movable arm subsequent to the actuation of the switch means, but prior to the closing of the main contacts of the circuit breaker. Such resilient members, however, tend to be unreliable and unpredictable in operation.

SUMMARY AND OBJECTS OF THE INVENTION A primary object of the invention, therefore, is to provide an actuator arrangement for the auxiliary switch of a circuit breaker whereby the auxiliary switch is actuated prior to closing of the circuit breaker contacts and at a predicable point during the movement of the movable arm toward the contacts closed position.

A further object is to provide an arrangement whereby the auxiliary switch is in its relaxed or least tensioned condition when the circuit breaker is in its normal or closed contacts condition.

A still further object is to provide a remote indication of the condition of the circuit breaker by releasing the actuator of the auxiliary switch prior to the closing of the circuit breaker contacts, rather than by depression of the actuator upon closing of the main contacts.

Another object is to provide an actuator arrangement for a circuit breaker whereby the movement of the actuating member is limited positively at the extreme ends of its path of movement.

These and other objects of the invention are achieved by means ofa member pivoted to the frame of the circuit breaker, driven adjacent one end thereof by a connection to the movable arm and positioned to engage an auxiliary switch at its other end depending upon the position of the movable arm. Provision is made that the plunger of the switch means is in its most relaxed condition during the time that the circuit breaker is in its contacts closed condition.

The foregoing and other objects of the invention, the principle of the invention, and the best mode in which it is contemplated applying such principles will more fully appear from the following description and accompanying drawing in illustration thereof.

BRIEF DESCRIPTION OF THE VIEWS In the drawings:

FIG. 1 shows the circuit breaker assembly of the invention in side elevation with one of the half-cases partially broken away to expose the operating mechanism in the contacts closed position and the actuator out of engagement with the auxiliary switch means;

FIG. 2 is a partial view similar to FIG. I showing the portion of the operating mechanism adjacent the auxiliary switch means with the main contacts of the circuit breaker in a position intermediate the fully open and fully closed positions and the actuator disengaged from the auxiliary switch;

FIG. 3 is a partial view similar to FIG. 2 showing the main circuit breaker contacts fully open and the actuator in engagement with the auxiliary switch means, with the extreme open circuit position of the movable contact arm shown in phantom; and

FIG. 4 is a view taken along the lines 4-4 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 of the drawings, the invention comprises an improved actuator 11 for incorporation into a known circuit breaker 12 for operating an auxiliary switch means 13 prior to the closing of the main circuit breaker contacts.

The circuit breaker 12 is generally similar to that described in US. Pat. No. 3,329,913 and in view of this similarity only a brief description of the operating mechanism of the circuit breaker will be given immediately hereinafter.

The circuit breaker mechanism 41 comprises a movable contact 42 carried by a movable arm 43 and engageable with a stationary contact 44, the latter carried by terminal 45. The movable arm 43 is connected by a flexible conductor 47 to one end of a coil (not shown) forming part of an electromagnetic device 50 (partly shown), the other end of the coil being connected to the terminal 46. The electromagnetic device '50 causes the collapse of the linkage mechanism 51, thereby tripping open the contacts 42 and 44.

Further, the movable arm 43 is biased by a spring 52 toward the open position of the contacts 42 and 44 and is mounted on a pin 53 which passes through an elongated slot 48'inthe movable arm, the pin 53 being carried by two spaced plates 54 which form a part of a main frame 59 for carrying the coil electromagnetic device 50. The end portions of the pin 53 extend beyond the frame plates 54 into holes formed in the opposed side walls of the half-cases 37 to properly locate and support the mechanism 41 inside the casing 40. Another pin 56, carried by the movable arm 43, has end portions which engage the spaced plates 54 to limit the opening movement of the arm 43, as shown in FIG. 3.

The movable arm 43 is also connected by a pin 57 to a toggle assembly 58, the latter being in turn connected to an arm 65 of the lever or link 60 by a pin 61. The link 60 pivots about a pin 64 which is also carried by the spaced plates 54, the end portions of the pin 64 extending beyond the plates 54 into holes formed in opposed side walls of the half-cases 37. A spring 55 is coiled on the pin 64 and has one end attached to one of the frame plates 54 and the other end of the spring 55 is in contact with the pin 61, the spring 55 being stressed at all times so as to bias the link 60 in a counterclockwise direction as seen in FIG. 1.

The link 60 will normally be held in one or the other of two stable positions, the contacts open" position, or the contacts closed position, FIG. 1. The pivotal link 60 is manually moved between these two positions by the operating handle 62 which is integral therewith. After tripping of the toggle assembly 58 in response to an overload, for instance, the link spring 55 automatically moves the link 60 counterclockwise from the contacts closed position, FIG. 1, to the contacts open position (not shown).

The frame 59 also forms a part of the electromagnetic device 50 which includes, as is well known in the art, a time delay tube (not shown) housing a spring biased magnetizable core (not shown) movable against the retarding action ofa suitable fluid to provide a time delay before tripping of the mechanism on certain overloads.

The operation of the linkage mechanism 51 and electromagnetic device 50 is specifically set forth in U.S. Pat. No. 3,329,913 and for purposes of brevity it will only be generally described herein as follows as the link 60 is moved clockwise from the contacts open position, i.e., the of position, to the position shown in FIG. 1, the toggle assembly 58 and the movable arm 43 all move down, against the bias of the spring 52, and move the movable contact 42 into engagement with the stationary contact 44 achieving the contacts closed position, i.e., the on" position as illustrated in FIG. 1.

Upon occurrence of a predetermined overload condition, assuming the circuit breaker to be in the contacts closed position, the armature 70, which is also part of the electromagnetic device 50, is attracted toward the pole piece (not shown), either after a time delay period or virtually instantaneously, depending on the overload condition. The armature 70 is pivoted on a pin 74 whose end portions are also carried by suitable holes in the frame plates 54. The armature 70 has formed integral therewith a trip finger71, and when the armature 70 pivots-towardthe pole piece 72, the trip finger 71'pivots to the right as seen in FIG. 1 and engages and trips the arm forming part of the linkage mechanism 51, which is opposite the trip finger 71 when the toggle assembly 58 is in the contacts closed position, FIG. 1, whereupon the toggle assembly 58 collapses and the movable arm 43 moves upward under the bias of spring 52 to open the contacts 42 and 44. The toggle assembly 58 is automatically relatched and simultaneously the pivotal link 60 is also moved to the contacts open position under the pressure applied by the spring 55.

As is well-known, a plurality of U-shaped magnetizable grids 66 are placed adjacent the movable and stationary contacts 42 and 44 to minimize any are that may form between the contacts upon opening. I

The case 40 of the circuit breaker 10 also includes an opening 25 out of which the operating handle 62 projects. The opening 25 is bounded by an approximately circular boss 26 formed integral with the circuit breaker case 40.

In addition to the main cavity in which the circuit breaker operating mechanism 41 is housed, the casing 40 provides for an auxiliary cavity 33 in which the auxiliary switch 13 is located. A more detailed description of the construction of the casing 40 to provide for the auxiliary cavity is given in U.S. Pat. No. 3,329,793. Briefly, however, the auxiliary cavity 33 is formed by extending one pair of abutting peripheral walls forming part of the half-cases 37 outwardly to form an opening. Each of the half-cases 37 defining the auxiliary cavity 33 is provided with a pair of recesses 39 on each side of the auxiliary switch. Two support pins 49 extend through aligned holes in the auxiliary switch 13 into these recesses to support the switch 13 in the auxiliary cavity 33.

The auxiliary switch 13 is located on the margin of the casing 40 containing the circuit breaker terminals 45 and 46 and is located intermediate these terminals. The auxiliary switch 13 carries three terminals 67, 68 and 69 and operates as a single pole double throw switch to connect common terminal 67 with either terminal 68 or 69, depending on the position of the operating plunger or rod 36. The rod 36 is continuously biased upwardly to a first position but is movable against this bias to a second or depressed position.

The actuator 11 comprises an elongated actuating member 71 which is U-shaped in cross section and is pivotally supported approximately midway thereof on the pin 53. The arms 72 of the U-shaped member 71 are positioned immediately adjacent the movable arm on opposite sides thereof so as to straddle the lower portion of the movable contact arm 43. Each of the arms 72 has an elongated open-ended slot 73 formed therein, each of the slots 73 enclosing, at least in part, the stop pin 56 carried by the movable arm 43 to limit the upward movement of the movable arm 43 when moving to the contacts open position.

The base 74 of the U-shaped actuating member 71 extends in the direction of the operating rod 36 of the auxiliary switch 13 and engages or disengages the rod 36 depending upon the position of the movable contact arm 43.

In operation, when the movable contact arm 43 is in the open position (circuit breaker contacts disengaged) the actuating member 71 is pivoted by lever action to the position shown in FIG. 4, with the base 74 of the actuating member 71 in contact with and depressing the operating rod 36 of the auxiliary switch 13 so that the auxiliary switch is in a first condition signifying the contacts open condition of the circuit breaker.

When the operating handle 62 of the circuit breaker 12 is rotated to move the movable contact 42 toward engagement with the stationary contact 44, the movable arm 43 moves downward. This downward movement of the movable arm 43 applies a force to the slotted end of the actuating member 71 via the stop pin 56 to rotate the actuating member clockwise as seen in FIG. 2 which results in the movement of the base 74 of the actuating member 71 out of engagement with the operating rod 36 of the auxiliary switch 13 at a point prior to the closing of the circuit breaker contacts. FIG. 2 illustrates that the base 74 of the actuating member 71 disengages from the operating rod 36 prior to the closing of the main contacts of the circuit breaker. With the base 74 of the actuating member 71 disengaged from the operated rod of the auxiliary switch, the auxiliary switch moves to a second condition to indicate that the condition of the main circuit breaker is about to change or alternatively actuate a remote circuit prior to the making of the circuit breaker contacts 42 and 44. Further movement of the operating handle 62 results in the closing of the circuit breaker contacts and movement of the actuating member 71 to the position shown in FIG. 1.

The auxiliary switch actuator ll of the invention has several advantages over similar actuators used in the prior art. One advantage is that under normal operating conditions of the circuit breaker, the auxiliary switch is held in its most relaxed position for a greater percentage of the time. This is so because the normal position of a circuit breaker, the position which it is in most of the time, is the contacts closed position. During this time the base 74 of the actuating member 71 is in its uppermost position and disengaged from the operating rod 36 of the auxiliary switch, with the result that the biasing spring which urges the rod 36 continuously upwardly is in its most relaxed or untensioned condition. Operation in this manner may contribute to a longer operating life for the auxiliary switch.

In addition, as alluded to above, in prior art arrangements for operating an auxiliary svrfitch prior to the closing of the main contacts of the circuit breaker, it is common to have the operating rod of the auxiliary switch depressed directly by the movable contact arm or indirectly by the movable arm via an intermediate link near the beginning of the downward movement of the movable arm, both of these arrangements necessitating the use of a means to absorb the downward movement ofthe movable arm subsequent to the actuation of the auxiliary switch, so as to prevent damage to the auxiliary switch. A typical prior art arrangement for the purpose of absorbing this subsequent movement incorporates a resilient arm attached either to the auxiliary switch housing or to the circuit breaker operating mechanism which responds tothe movement of the movable arm to depress the operating rod of the auxiliary switch, but which, due to its bending characteristic, applies a smaller force to the operating rod subsequent to the actuation of the switch which can be absorbed without damage to the switch.

However, in the arrangement of the invention the necessity of an intermediate absorbing member is eliminated since the operating rod 36 is released rather than depressed in response to the movement of the movable arm 43 toward the contacts closed position with the results that the motion of the movable arm subsequent to the actuation of the auxiliary switch is not transmitted to the operating rod 36 of the auxiliary switch 13.

Further advantages of the invention become apparent upon consideration of the various positions of the movable arm in moving between the contacts open and closed positions. During the movement of the movable contact arm 43 downward to the contacts closed position, FIG. I, the combination of the upward force exerted by the spring 52 on the underside of the movable arm 43 and the downward force exerted by the toggle assembly 58 via pin 57, pivots the end of the movable arm having the elongated slot 48 upward so that the pin 53 comes to rest in the lower portion of the slot 48 when the contacts 42 and 44 are closed. Also, during this downward movement the actuating member 71 is rotated clockwise and the base 74 thereof is rotated away from the operating rod 36 of the auxiliary switch, as explained previously. The base 74 continues this movement until the contacts 42 and 44 are engaged (FIG. 1). The engagement of the contacts 42 and 44 provide a positive limit to the upward movement of the base 74.

When the contacts are opened, the final position of the movable contact arm may be at or between the extremes shown in FIG. 3, depending on the momentum attained by the movable arm and the operating mechanism during the opening movement, and also upon the mechanical variables such as spring tensions and part tolerances. As can be noted from FIG. 4, the extreme open position of the movable arm 43 shown in solid lines results from the positive limiting action of stop pin 56 against the frame plates 54 in combination with the retention of the slot 48 in its uppermost position relative to the pin 53. This may result from a slow manual opening of the handle 62 which imparts little momentum to the operating mechanism 51.

The second extreme open position of the movable arm 43 shown in phantom in FIG. 3 may be achieved when the operating mechanism 41 is opened manually with a rapid movement of the handle 62 or alternately when it is opened under the bias of the opening spring 52 subsequent to the collapse of the toggle assembly 58 after the occurrence of an electrical overload. This second extreme position results from the combined action of the stop pin 56 against the plates 54 and the torque on the contact side of the movable arm 43 during the opening movement which tends to pivot the arm 43 about the stop pin 56 to move the slot 48 downward relative to the pivot pin 53.

As is apparent from the above discussion, the position of the base 74 of the actuating member 71 remains constant independent of the various open positions of the movable arm 43 shown in FIG. 3. This is due to the fact that the actuator is fixedly pivoted on the pin 53 and is driven by the stop pin 56, the position of which remains relatively constant during movement of the slot 48 on the movable arm 43 of its various positions shown in FIG. 3. Thus, irrespective of the possible open positions of the movable arm 43, the final position of the actuating member 71 remains constant.

Having described this invention, what I claim is:

l. A circuit breaker comprising a case, a movable contact, a stationary contact, a movable arm for carrying said movable contact, an operating handle projecting out of said case, a collapsible linkage coupling said handle to said arm and operable in conjunction with the movement of said handle to move said movable arm between open and closed positions, whereby said contacts are moved between the contacts open and contacts closed positions, respectively, means for continuously biasing said movable arm toward said open posi tion, tripping means for collapsing said collapsible linkage upon the occurrence of a preselected condition, a frame, means for pivotally supporting said movable arm from said frame, an auxiliary switch carried by said case, an actuating member, a first portion of said member located adjacent said auxiliary switch and engageable therewith, means for connecting a second portion of said member to said movable arm, and means for pivotally supporting said member from said frame at a third portion intermediate said first and second portions.

2. The combination recited in claim 1 wherein said member is U-shaped in cross-section, the arms of said U being located on opposite sides of said movable arm.

3. The combination recited in claim 1 wherein said means for pivotally supporting said movable arm and said means for pivotally supporting said member comprise a single pin.

4. The combination recited in claim 1 wherein said means for connecting said member to said movable arm in said first portion comprises a pin carried by said movable arm and an open-ended slot located in said first portion of said member, said pin being located at least in part within said slot.

5. The combination recited in claim 4 wherein said pin engages said frame to limit the upward movement of said arm due to said biasing means.

6. A circuit breaker comprising a case, a movable contact, a stationarycontact, a movable arm for carrying said movable contact, an operating handle projecting out of said case, a collapsible linkage coupling said handle to said arm and operating in conjunction with the movement of said handle to move said movable arm between open and closed positions, whereby said contacts are moved between the contacts open and contacts closed positions respectively, means for continuously biasing said movable arm toward said open position, tripping means for collapsing said collapsible linkage upon the occurrence of a preselected condition, means for pivotally supporting said movable arm, and auxiliary switch means carried by said case, said switch means including an operating rod biased toward a first position, corresponding to a first condition of said switch, and movable against said bias to a second position corresponding to a second condition, and means pivotally supported adjacent said movable arm and continuously coupled to said movable arm for concurrent rotation in conjunction therewith for releasing said rod to move to said first position in response to the movement of said movable arm toward said closed position, and for moving said rod against said bias in response to the movement of said movable arm toward said 0 en position.

7. he combination recited in claim 6 wherein said means pivotally supported adjacent said movable arm comprises a member, a first portion of said member located adjacent said rod and engageable therewith, means for connecting a second portion of said member to said movable arm, and means for pivotally supporting said member from said frame at a third portion intermediate said first and second portions.

8. The combination recited in claim 7 wherein said member is U-shaped in cross-section, the arms of said U being located on opposite sides of said movable arm.

9. The combination recited in claim 8 wherein said means for pivotally supporting said movable arm and said means for pivotally supporting said member comprise a single pin.

10. The combination recited in claim 9 wherein said means for connecting said member to said movable arm in said first portion comprises a pin carried by said movable arm and an open-ended slot located in said first portion of said member and said pin being located at least in part within said slot.

11. A circuit breaker comprising a case, relatively movable contacts enclosed by said case, a collapsible linkage enclosed by said case and coupled to said contacts for moving said contacts between open and closed positions, a contact arm for carrying one of said contacts, means for mounting said arm for pivotal movement, switch means carried by said case including an operating member biased toward a first position and movable against the bias to a second position, and actuator, and means for positively coupling said actuator to said arm for continuously transmitting the pivotal movement on said arm to said actuator whereby said actuator follows the pivotal movement of said arm.

12. A circuit breaker comprising a case, relatively movable contacts enclosed by said case, one of said contacts carried by an arm mounted for rotation about a pivot pin, a handle projecting from said case, a collapsible linkage coupled intermediate said arm and said handle for moving said contacts between open and closed positions, switch means carried by said case including a member for operating said switch between first and second conditions, a rigid actuator, a first portion of said actuator extending away from said pin adjacent said member and engageable therewith, a second portion of said actuator extending away from said pin in the direction of said movable contact and coupled to said arm, said actuator being pivotally supported at a third portion intermediate said first and second portions whereby pivotal movement of the arm is transferred via said actuator to said member to operate it between said first and second conditions.

13. The combination recited in claim 12 wherein said actuator is pivotally supported on said pin; 

1. A circuit breaker comprising a case, a movable contact, a stationary contact, a movable arm for carrying said movable contact, an operating handle projecting out of said case, a collapsible linkage coupling said handle to said arm and operable in conjunction with the movement of said handle to move said movable arm between open and closed positions, whereby said contacts are moved between the contacts open and contacts closed positions, respectively, means for continuously biasing said movable arm toward said open position, tripping means for collapsing said collapsible linkage upon the occurrence of a preselected condition, a frame, means for pivotally supporting said movable arm from said frame, an auxiliary switch carried by said case, an actuating member, a first portion of said member located adjacent said auxiliary switch and engageable therewith, means for connecting a second portion of said member to said movable arm, and means for pivotally supporting said member from said frame at a third portion intermediate said first and second portions.
 1. A circuit breaker comprising a case, a movable contact, a stationary contact, a movable arm for carrying said movable contact, an operating handle projecting out of said case, a collapsible linkage coupling said handle to said arm and operable in conjunction with the movement of said handle to move said movable arm between open and closed positions, whereby said contacts are moved between the contacts open and contacts closed positions, respectively, means for continuously biasing said movable arm toward said open position, tripping means for collapsing said collapsible linkage upon the occurrence of a preselected condition, a frame, means for pivotally supporting said movable arm from said frame, an auxiliary switch carried by said case, an actuating member, a first portion of said member located adjacent said auxiliary switch and engageable therewith, means for connecting a second portion of said member to said movable arm, and means for pivotally supporting said member from said frame at a third portion intermediate said first and second portions.
 2. The combination recited in claim 1 wherein said member is U-shaped in cross-section, the arms of said U being located on opposite sides of said movable arm.
 3. The combination recited in claim 1 wherein said means for pivotally supporting said movable arm and said means for pivotally supporting said member comprise a single pin.
 4. The combination recited in claim 1 wherein said means for connecting said member to said movable arm in said first portion comprises a pin carried by said movable arm and an open-ended slot located in said first portion of said member, said pin being located at least in part within said slot.
 5. The combination recited in claim 4 wherein said pin engages said frame to limit the upward movement of said arm due to said biasing means.
 6. A circuit breaker comprising a case, a movable contact, a stationary contact, a movable arm for carrying said movable contact, an operating handle projecting out of said case, a collapsible linkage coupling said handle to said arm and operating in conjunction with the movement of said handle to move said movable arm between open and closed positions, whereby said contacts are moved between the contacts open and contacts closed positions respectively, means for continuously biasing said movable arm toward said open position, tripping means for collapsing said collapsible linkage upon the occurrence of a preselected condition, means for pivotally supporting said movable arm, and auxiliary switch means carried by said case, said switch means including an operating rod biased toward a first position, corresponding to a first condition of said switch, and movablE against said bias to a second position corresponding to a second condition, and means pivotally supported adjacent said movable arm and continuously coupled to said movable arm for concurrent rotation in conjunction therewith for releasing said rod to move to said first position in response to the movement of said movable arm toward said closed position, and for moving said rod against said bias in response to the movement of said movable arm toward said open position.
 7. The combination recited in claim 6 wherein said means pivotally supported adjacent said movable arm comprises a member, a first portion of said member located adjacent said rod and engageable therewith, means for connecting a second portion of said member to said movable arm, and means for pivotally supporting said member from said frame at a third portion intermediate said first and second portions.
 8. The combination recited in claim 7 wherein said member is U-shaped in cross-section, the arms of said U being located on opposite sides of said movable arm.
 9. The combination recited in claim 8 wherein said means for pivotally supporting said movable arm and said means for pivotally supporting said member comprise a single pin.
 10. The combination recited in claim 9 wherein said means for connecting said member to said movable arm in said first portion comprises a pin carried by said movable arm and an open-ended slot located in said first portion of said member and said pin being located at least in part within said slot.
 11. A circuit breaker comprising a case, relatively movable contacts enclosed by said case, a collapsible linkage enclosed by said case and coupled to said contacts for moving said contacts between open and closed positions, a contact arm for carrying one of said contacts, means for mounting said arm for pivotal movement, switch means carried by said case including an operating member biased toward a first position and movable against the bias to a second position, and actuator, and means for positively coupling said actuator to said arm for continuously transmitting the pivotal movement on said arm to said actuator whereby said actuator follows the pivotal movement of said arm.
 12. A circuit breaker comprising a case, relatively movable contacts enclosed by said case, one of said contacts carried by an arm mounted for rotation about a pivot pin, a handle projecting from said case, a collapsible linkage coupled intermediate said arm and said handle for moving said contacts between open and closed positions, switch means carried by said case including a member for operating said switch between first and second conditions, a rigid actuator, a first portion of said actuator extending away from said pin adjacent said member and engageable therewith, a second portion of said actuator extending away from said pin in the direction of said movable contact and coupled to said arm, said actuator being pivotally supported at a third portion intermediate said first and second portions whereby pivotal movement of the arm is transferred via said actuator to said member to operate it between said first and second conditions. 